POS0834 COMPARISON OF NOVEL INFLAMMATORY MARKERS IN IDIOPATHIC AND SECONDARY LEUKOCYTOCLASTIC VASCULITIS
Authors: O. Dhrif, M. S. Hamdi, I. Kechaou, I. Boukhris, E. Cherif, S. Azzabi, L. Ben Hassine
Journal: Annals of the Rheumatic Diseases (2022)

Background Positive diagnosis of Leukocytoclastic vasculitis (LV) is easy to establish via cutaneous biopsy, while etiologic diagnosis can be quiet challenging which leads to a still concerning high rate of idiopathic LV (ILV). Novel inflammatory Ratios such as platelet to lymphocyte ratio (PLR), neutrophil to lymphocyte ratio (NLR), C-reactive protein (CRP) to albumin ratio (CAR) and Fibrinogen to albumin ratio (FAR) have been recently described in multiple inflammatory pathologies, but their description and role in distinguishing idiopathic and secondary LV (SLV) is yet to be explored. Objectives We conducted a study aiming to compare new inflammatory markers and their potential role in distinguishing both LV subtypes. Methods Cross sectional study in which LV diagnosis was retained on cutaneous biopsy examination from January 2001 to November 2020. Patient’s clinical assessment and laboratory data measured for each patient included age and sex, aspect and extent of the LV cutaneous lesions, neutrophil (N) count, lymphocyte (L) count, platelet (PLT) count, CRP, albumin (ALB), gammaglobulin (GG). PLR, NLR, CAR and FAR were calculated according to the results of individual items. We have also defined the number of positive aetiological examination (NPE) as the sum in a unique patient of the positive para clinical examinations involved in the etiological assessment of LV. Categorical variables were compared with the χ2 -test. Comparisons of the differences of continuous variables were performed by the Mann–Whitney U test or Student’s t-test. Pearson correlation ratio was used for linear correlation analysis. Results A total of 77 patients were included in this study with 52 patients in the SLV group and 25 patients in the ILV group, demographic and clinical characteristics of both groups were distributed respectively as followed: mean age at diagnosis was 44+/-18 vs 49+/-21, gender ratio was at 29/23 vs 11/14, petechial aspect (89% vs 92%), ecchymotic aspect (64% vs 52%), necrotic aspect (46% vs 28%), extent to the trunk (31% vs 46%) and extend to upper limbs (50% vs 55%), none of these differences were statistically significant (p&gt;0.05). Aetiologies of SLV were distributed as followed: IGA vasculitis 16 cases, Sjogren’s syndrome 6 cases, Systemic lupus erythematous and cryoglobulinemia 5 cases each, Viral hepatitis and infectious endocarditis 3 cases each, rheumatoid arthritis, granulomotosis with polyangeitis, post streptococcal and chlamydia infection 2 cases each, Castleman’s disease, tuberculosis, lymphoma, primary APS, periarteritis nodosa and parvovirus B19 infection 1 case each. Comparison of PLR, NLR, CAR and FAR showed statistically significant difference in means between SLV and ILV groups with 199 (177-309) vs 127 (79-193) (p=0.01) for PLR, 3.6 (1.9-5.1) vs 2.3 (1.7-3.4) (p=0.048) for NLR, 1.9mg.g-1 (0.4-3.6) vs 0.6mg.g-1 (0.2-1.9) (p=0.043) for CAR, 156mg.g-1 (91-192) vs 108mg.g-1 (82-148) (p=0.034) for FAR. PLR, CAR and FAR were significantly positively correlated to NPE (r=0.463, P&lt;0.001; r=0.434, P&lt;0.001 and r=0.411, P&lt;0.001 respectively), there was no significant correlation between NLR and NPE (r=0.165, P=0.151). Conclusion In conclusion, this is the first study to explore the role of PLR, NLR, CAR and FAR in LV, it demonstrates that elevation of these ratios is a good predictor of SLV and that PLR, CAR and FAR were correlated with NPE in LV, which leads us to suggest to exhaustively explore patients with elevated ratios in order to make sure not to miss any underlying aetiology and provide more specific management for LV patients. Disclosure of Interests None declared